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A radio propagation beacon is a radio beacon, which is mainly used for investigating the propagation of radio signals. Currently most radio propagation beacons use amateur radio frequencies.(26) They can be found on HF, VHF, UHF, and microwave frequencies. Microwave beacons are also used as signal sources to test and calibrate antennas and receivers.[1][2] Andy Talbot, G4JNT, gives the following definition for beacons licensed in the Amateur Radio service: A station in the Amateur Service or Amateur Satellite Service that autonomously transmits in a fixed format, which may include repeated data or information, for the study of propagation, determination of frequency or bearing, or for other experimental purposes.[1]

History

The earliest record of radio propagation beacons goes back to World War II, when the German military operated propagation beacons on wavelengths of approximate 80 m and 10 m. Many propagation beacons were installed during the International Geophysical Year 1957-1958 These included amateur radio beacons OZ7IGY and GB3IGY (later GB3RAL) on 144 MHz, which are still operational, as well as the now defunct DM3IGY in East Germany on 28001 kHz. (19) GB3IGY transmitted with the unusual for the time high power of 1 kW. It was situated at Badgers Mount, Sevenoaks, England and was operated by Ken Ellis, G5KW.(22)

Transmission characteristics

A CW beacon keyer based on discrete CMOS digital chips.

The majority of propagation beacons operate in continuous wave (CW or A1A) and transmit their identification (callsign and location) in Morse code. Some of them send long dashes (sometimes at varying power levels) to facilitate signal strength measurement. A small number of beacons transmit Morse code by frequency shift keying (F1A). A few beacons transmit signals in digital modulation modes, like radioteletype (F1B) and PSK31 (G1B).

Most beacons consist of a simple digital keyer, based on discrete digital electronics or a microcontroller, and a low power transmitter or tranceiver. FT-897, a budget HF tranceiver produced by Yaesu/Vertex, has a programmable beacon mode and is used in some temporary propagation beacon installations. Recently K6HX published a versatile Morse code keyer design based on the popular Arduino microcontroller platform.

Antennas usually are types with low directivity. There are exceptions, however, like the high power beacons with directional antennas, specifially set up for transatlantic VHF propagation experiments.

160 meters beacons

The IARU Region 2 (North and South America) bandplan reserves the range 1999 kHz to 2000 kHz for propagation beacons.

60 meters beacons

In addition to the DARC and RSBG beacon projects on 5195 and 5290 kHz (see below), Eddie Bellerby of UDXF discovered in March 2011 a new CW beacon on 5206 kHz, sending LX0HF, presumably from Luxembourg.[13] Further intelligence indicates that the beacon is operated by Philippe LX2A/LX7I of the Luxembourg Amateur Radio Society.[14] Two more european beacons are listed on 5 MHz, OV1BCN on 5290 kHz, operated by OZ1FJB and OK1IF on 5258.5 kHz from the Czech Republic, though their current status is unclear.

30 meters beacons

Callsign

Frequency

Locator

Details

DK0WCY

10144.0 kHz

JO44VQ

DARC

IK3NWX

10137.3 kHz

JN55VF

nr Monselice, PD 15m asl

10 meters beacons

QSL card from K5DZE 28 MHz beacon at Dry Ridge, KY.

Most HF radio propagation beacons are found in the 10 meters (28 MHz) frequency band, where they are good indicators of Sporadic E ionospheric propagation. According to IARU bandplans, the following 28 MHz frequencies are allocated to radio propagation beacons:

IARU Region

Beacon allocations

R1

28190-28199 Regional Time Shared

28199-28201 WW Time Shared

28201-28225 Continuous Duty

R2[3]

28190-28199 Regional Time Shared

28199-28201 IBP/NCDXF

28201-28225 Beacons, continuous duty

28225-28300 Shared

R3

28190-28200 IBP

40 MHz beacons

The first radio propagation beacon on 40 MHz is OZ7IGY in Jystrup, Denmark (JO55WM) and transmits on 40071 kHz 40021 kHz. Transmitted power is 20 W to a dipole antenna. The beacon is frequency- and time-locked to GPS. The sequence is programmed to send PI4 , followed by a short pause, and then the call sign and grid locator sent in CW, then a pause, and a carrier until start of the next cycle. PI4 is a digital mode specifically designed for beacons and propagation studies, similar to JT4 and WSPR. To decode PI4, tune 800 Hz below the nominal frequency.

6 meters (50 MHz) beacons

Antenna tower of LX0SIX and LX0FOUR beacons

In the 6 meters (50 MHz) band, beacons traditionally operate in the lower part of the band, in the range 50000 kHz to 50080 kHz. Due to unpredictable and intermittent long distance propagation, usually achieved by a combination of ionospheric conditions, beacons are very important in providing early warning for 50 MHz openings.

The ARRL bandplan recommends 50060 to 50080 kHz for beacons in the United States.

In Australia beacons operate from 50280 to 50350 kHz.

The new IARU Region 1 bandplan moves 50 MHz beacons in a new allocation, 50400 to 50500 kHz.

4 meters (70 MHz) beacons

General beacon operations

Numerous beacons operate on 70 MHz in recent years. Their main purrpose is to dected the relativley rare and extreme Es (sporadic E) opennings, which exceed 70 MHz.

There is no definite international beacon allocation, due to various countries having different amateur radio allocations in this band. Generally beacons operate near the bottom end (70.000-70.100 MHz).(11) (12). Most respect the RSGB bandplan, staying below 70.050 MHz.

Special beacon allocations

USA: 70.005 MHz is allocated to the WE9XFT beacon. Transmits from Bedford, VA, under an FCC experimental license issued to Brian Justin, WA1ZMS, with a power of 3 kW. In 2012 this beacon shall transmit from the same location under new callsign WF9XRU.

Austria: 70.045 MHz is allocated to the OE5QL beacon.

Hong Kong: 71.757 MHz is allocated to the VR2FOUR beacon.

VHF/UHF beacons

GB3VHF propagation beacon (144 MHz)

Beacons on 144 MHz and higher frequencies are mainly used to identify tropospheric radio propagation openings. It is not uncommon for VHF and UHF beacons to use directional antennas. Frequency allocations for beacons on VHF and UHF bands vary widely in different ITU/IARU regions and countries.

Band

Beacon Sub-band (MHz)

IARU R1

IARU R2

IARU R3

2 m

144.400-144.490

144.275–144.300

Unknown

1.25 m

N/A

222.050–222.060

N/A

70 cm

432.800-432.990

432.300–432.400

Unknown

33 cm

N/A

Varies Locally

N/A

23 cm

1,296.800-1,296.990

1,296.070-1,296.080

Unknown

13 cm

2,320.800-2,320.990

2,304.300-2,304.400

Unknown

The current allocation in the United Kingdom, which also reflects IARU Region 1 recommendations, is the following:[4]

Band

Beacon allocation (kHz)

4 m

70,000-70,030

2 m

144,400-144,490

70 cm

432,800-432,990

23 cm

1296,800-1296,990

ON0EME moon beacon

Screen capture of ON0EME by G4DZU

A beacon specifically for earth-moon-earth (EME or "moonbounce") reception became operational in 2012 in Belgium. The beacon uses call sign ON0EME and transmits on 1296.0 MHz with a very high power of 1000 kW ERP. The antenna is a solid parabolic reflector with a diameter of 3.7 m. [17]

144 MHz transatlantic beacons

A number of VHF beacons have been installed on both shores of the Atlantic Ocean, as an early warning system for exceptional sporadic-E (Es) conditions, which shall allow transatlantic QSOs on 2 m. The followng list includes most beacons, not all of them are always operational.[23]

Indian Ocean beacon project

An Australian ham radio group has set up a beacon to investigate if there is any VHF ducting between Australia and South Africa. Beacon VK6RIO is located in Perth, W. Australia and operates on 144.950 MHz. The beacon transmits 100 watts into four 8-element Yagis with digital Chirp modulation. This special modulation scheme can be detected some 50 dB below the noise floor.

The beacon is GPS locked both in frequency, time and Chirp synchronisation. In order to detect the Chirp beacon, the receiving station requires a GPS locked Software Defined Radio (SDR), a GPS locked 144 MHz down-converter and 1 PPS signal from a GPS receiver to time stamp received signals. Open source PC software by Hermann, DL3HVH, shall be made available for processing the received signals.

SHF and microwave beacons

In addition to identifying propagation, microwave beacons are also used as signal sources to test and calibrate antennas and receivers. SHF beacons are not as common as beacons on the lower bands, and beacons above the 3 cm (10 GHz) band are unusual.

Band

Beacon Sub-band (MHz)

IARU R1

IARU R2

IARU R3

9 cm

3,400.800-3,400.995

3,456.300-3,456.400

Unknown

5 cm

5,760.800-5,760.995

5,760.300-5,760.400

Unknown

3 cm

10,368.800-10,368.995

10,368.300-10,368.400

Unknown (25)

1.2 cm

24,048.800-24,048.995

Beacons are rare

Optical and infrared beacons

Recently some groups of radio amateurs, especially in Great Britain, experiment with two-way communications on optical wavelengths. This activity has led to the design and installation of a few beacons operating on optical wavelengths. These beacons transmit modulated light using high intensity LEDs and are used mainly for equipment setting and calibration. An interesting example is the optical beacon located at GB3CAM (Wyton, UK) operating at 628 nm.[16]

License-free experimental beacons

These are extremely low power experimental beacons which operate legally without a license on specific bands, which are reserved for very short range radio transmissions or for industrial, scientific and medical devices (ISM) and in which a limited level of radiated RF energy is allowed. They are operated as radio propagation experiments by radio amateurs and other radio hobbyists.

Beacon projects

NCDXF-IARU beacon setup

Most radio propagation beacons are operated by individual radio amateurs or amateur radio societies and clubs. As a result, there are frequent additions and deletions to the lists of beacons. There are, however a few major projects coordinated by organizations like the International Telecommunications Union and the International Amateur Radio Union.

IARU Beacon Project

The International Beacon Project (IBP), which is coordinated by the Northern California DX Foundation (NCDXF) and the International Amateur Radio Union (IARU), consists of 18 HF propagation beacons worldwide, which transmit in turns on 14100 kHz, 18110 kHz, 21150 kHz, 24930 kHz, and 28200 kHz. [5] The IARU/NDXF beacons transmit in turns on the five designated frequencies according to the following schedule, which repeats every 3 minutes:

Slot

DXCC entity

Call

Location

Latitude

Longitude

Grid Sq

14100

18110

21150

24930

28200

Operator

01

United Nations

4U1UN

New York City

40º 45' N

73º 58' W

FN3ØAS

00.00

00.10

00.20

00.30

00.40

UNRC

02

Canada

VE8AT

Eureka, Nunavut

79º 59' N

85º 57' W

EQ79AX

00.10

00.20

00.30

00.40

00.50

RAC

03

United States

W6WX

Mt. Umunhum

37º 09' N

121º 54' W

CM97BD

00:20

00.30

00:40

00.50

01:00

NCDXF

04

Hawaii

KH6WO

Laie

21º 38' N

157º 55' W

BL11AP

00.30

00.40

00.50

01.00

01.10

(Off)

05

New Zealand

ZL6B

Masterton

41º 03' S

175º 36' E

RE78TW

00.40

00.50

01.00

01.10

01.20

NZART

06

Australia

VK6RBP

Rolystone

32º 06' S

116º 03' E

OF87AV

00.50

01.00

01.10

01.20

01.30

WIA

07

Japan

JA2IGY

Mt. Asama

34º 27' N

136º 47' E

PM84JK

01.00

01.10

01.20

01.30

01.40

JARL

08

Russia

RR9O

Novosibirsk

54º 59' N

82º 54' E

NO14KX

01.10

01.20

01.30

01.40

01.50

SRR

09

Hong Kong

VR2B

Hong Kong

22º 16' N

114º 09' E

OL72BG

01.20

01.30

01.40

01.50

02.00

HARTS

10

Sri Lanka

4S7B

Colombo

6º 6' N

80º 13' E

NJ06CC

01.30

01.40

01.50

02.00

02.10

RSSL

11

South Africa

ZS6DN

Pretoria

25º 54' S

28º 16' E

KG44DC

01:40

01.50

02:00

02:10

02:20

ZS6DN

12

Kenya

5Z4B

Kariobangi

1º 15' S

36º 53' E

KI88KS

01.50

02.00

02.10

02.20

02.30

ARSC

13

Israel

4X6TU

Tel Aviv

32º 03' N

34º 46' E

KM72JB

02:00

02:10

02:20

02.30

02:40

IARC

14

Finland

OH2B

Lohja

60º 19' N

24º 50' E

KP2Ø

02:10

02:20

02:30

02:40

02:50

SRAL

15

Madeira

CS3B

Santo da Serra

32º 43' N

16º 48' W

IM12OR

02.20

02.30

02.40

02.50

00.00

ARRM

16

Argentina

LU4AA

Buenos Aires

34º 37' S

58º 21' W

GFØ5TJ

02:30

02:40

02:50

00.00

00:10

ARC

17

Peru

OA4B

Lima

12º 04' S

76º 57' W

FH17MW

02.40

02.50

00.00

00.10

00.20

RCP

18

Venezuela

YV5B

Caracas

10º 25' N

66º 51' W

FK6ØNJ

02:50

00.00

00:10

00:20

00:30

RCV

The original NCDXF/IARU beacon project, coordinated by John W6ISQ, consisted of nine 100W beacons which operated only on 14100 kHz on a coordinated 10 minute sequence. The beacons used to send a longer callup sequence, like "QST DE 4U1UN/B BEACON" followed by dashes with 100 W, 10 W, 1 W, and 100 mW, finally ending with "4U1UN/B SK". The original beacons were 4U1UN/B, W6WX/B, KH6O/B, JA2IGY, 4X6TU, OH2B, CT3B, ZS6DN and LU4AA. This network evolved into its current format with 18 beacons on five frequencies around 1999.(15) The current beacons consist of a Kenwood TS-50 tranceiver, a beacon controller, a vertical antenna and a GPS unit.

ITU sponsored beacons

As part of an International Telecommunications Union-funded project, radio propagation beacons were installed by national authorities at Sveio, Norway (callsign LN2A, 59.60420N - 5.291670E) and at Darwin, Australia (callsign VL8IPS, 12.60420S - 131.29200E). The beacons operated on frequencies 5471.5 kHz, 7871.5 kHz, 10408.5 kHz, 14396.5 kHz, and 20948.5 kHz.(6)(15)(27) Since 2002, there have been no reception reports for these beacons and the relevant ITU web pages have been removed. (7)(20)

HF Field-Strength measurement campaign

For a number of years, ITU-R Study Group 3 has been promoting a world-wide HF field-strength measurement campaign, the impetus for which arose from WARC HFBC-87 and the request for improved accuracy in HF propagation prediction. At that time, the Study Group recognised that significant improvements in HF propagation prediction methods needed a substantial body of new measurement data and to that end, administrations and organisations were invited to participate in the measurement campaign, either by installing suitable transmitters or by collecting long-term data from appropriate receiving systems. The campaign is specified in Recommendation ITU-R P.845 'HF field-strength measurement' and comprises a world-wide network of transmitters and receivers using coded transmissions on pre-determined frequencies.

The reasons for the campaign and the continuing need for participation in it, are underlined in Resolution ITU-R 27 (HF field-strength measurement campaign). So far, regular transmissions are being provided by the Administrations of Australia and Norway. Details of the transmitter in Norway, operated by the Norwegian Telecommunications Authority and Telenor Broadcasting, are given below:

Signal duration and format: as specified in Recommendation ITU-R P.845; 4 min for each frequency, 20 min for all five frequencies according to the following schedule:

Reference frequency (kHz)

Minutes after each hour

14395

00 - 20 - 40

20945

04 - 24 - 44

5470

08 - 28 - 48

7870

12 - 32 - 52

10407

16 - 36 - 56

Administrations and organizations participating in the work of ITU-R are invited to consider the possibility of participating in the campaign, either through the provision of transmissions or by the collection of field strength measurement data, both in accordance with the specifications given in Recommendation ITU-R P.845. For further details on the campaign, including the availability of a suitable receiving system, please contact the ITU-R Counsellor for Study Group 3 (Dr. Kevin A. Hughes) at ITU Headquarters, in Geneva.

The Norwegian Telecommunications Authority and Telenor Broadcasting would be pleased to acknowledge reception reports of LN2A with a QSL card.

Signal duration and format: as specified in Recommendation ITU-R P.845; 4 min for each frequency, 20 min for all five frequencies according to the following schedule:

Reference frequency (kHz)

Minutes after each hour

5470

00 - 20 - 40

7870

04 - 24 - 44

10407

08 - 28 - 48

14395

12 - 32 - 52

20945

16 - 36 - 56

Reception reports could be sent beacon@ips.gov.au

DARC beacon project

The Deutscher Amateur Radio Club (DARC) sponsors two beacons which transmit from Scheggerott, near Kiel (54.68750N - 9.791670E, JO44VQ). [8] These beacons are DRA5 on 5195 kHz and DK0WCY on 10144 kHz. In addition to identification and location, every 10 minutes these beacons transmit solar, geomagnetic and ionospheric bulletins. Transmissions are in Morse code (CW) for aural reception, RTTY (45 baud 170 Hz at HH+10) and PSK31 (at HH+50). [9] DK0WCY operates also a limited service beacon on 3579 kHz at 0720-0900 and 1600-1900 local time.

RSGB 5 MHz beacon project

The Radio Society of Great Britain (RSGB) operates three radio propagation beacons on 5290 kHz, which transmit in sequence, for one minute each, every 15 minutes. The project includes GB3RAL near Didcot (51.56250N - 1.291670W, IO91IN), GB3WES in Cumbria (54.56250N - 2.6250W, IO84QN) and GB3ORK in the Orkney Islands (59.02080N - 3.208330W, IO89JA).

Beacon GB3RAL, which is located at the Rutherford-Appleton Laboratory (RAL), also transmits continuously on 28215 kHz and on a number of low VHF frequencies (40050, 50053, 60053 and 70053 kHz).[10]

As of August 2017 the 5 MHz beacon at Didcot is not operational. The other two beacons are active. In addition to Morse code, beacon GB3ORK also transmits in JT9 on the minute following its regular transmission.

U.S. Navy beacons

A radio propagation beacon with callsign NAF was installed in 1983 at Cape Prince, Wales, AK. It transmitted both CW and FSK identification with 100 W to a three-band fan dipole on 5604, 11004 and 16804 kHz. The project, which included reception sites at Fairbanks, AK, Seattle, WA, State College, PA and San Diego, CA, was coordinated by the U.S. Naval Security Group Command and its purpose was to verify and calibrate HF propagation prediction software. (15) It is not known when the project was terminated.

Another propagation beacon was installed in 1991 at the Arctic Submarine Laboratory at Cape Prince of Wales, AK. The beacon operated on 25545 kHz and tranmitted the morse code letter "R". A reception facility existed at Fairbanks, AK, some 900 km away. The R beacon was used to study aurora and sporadic E events at high geographical latitudes.(18)

WSPR Network

This is an a large scale amateur radio propagation beacon project which uses the WSPR (Weak Signal Propagation Reporter) transmission scheme available with the WSJT software suite, created by Joe Taylor, K1JT. The loosely-coordinated beacon transmitters and receivers, collectively known as the WSPRnet, report the real-time propagation characteristics of a number of frequency bands and geographical locations via the Internet. The WSPRnet website provides detailed propagation report databases and real-time graphical maps of propagation paths. WSPR Network operates on the following amateur radio frequencies (USB dial settings in kHz) 136.0, 502.4, 1836.6, 3592.6, 5287.2, 7038.6, 101387.0, 14095.6, 18104.6, 21094.6, 24924.6, 28124.6, 50293.0, 70028.6 and 144489.0 kHz.

The future of radio propagation beacons

It seems that there is no longer an interest in HF radio propagation by international organizations, government departments or research institutes, therefore they shall be operated only as part of the amateur radio service.

A slow process is underway to supplement morse code (CW) identification, which is mostly suitable for aural reception, with digital modulation patterns. The RSGB beacons on 5290 kHz already transmit such code for 30" in each transmission. In the 2011 RSGB Convention, Bo OZ2M shall talk about the introduction of machine generated modulation to most radio propagation beacons, in order to enable automatic monitoring.

Beacon timing functions are also modernized. When more beacons share a frequency, they are synchronized by electronic clocks locked to GPS satellite transmissions.

Allocations vary by country. In Australia, VK3RMB is on 10368.536 MHz, VK3RGI on 10368.434 MHz and VK3RXX on 10368.530 MHz.

According to USA/FCC rules, a Beacon is defined as an amateur station transmitting communications for the purposes of observation of propagation and reception or other related experimental activities. (Part 79.3.a.9)

Beacon lists

Currently there are two regularly updated international beacon lists, compiled by Martin G3USF and Joost, ZS5S. Both lists are available on-line. An additional online list by WJ5O contains only 28 MHz (10 meter) beacons.

(a) Any amateur station licensed to a holder of a Technician, Technician Plus, General, Advanced or Amateur Extra Class operator license may be a beacon. A holder of a Technician, Technician Plus, General, Advanced or Amateur Extra Class operator license may be the control operator of a beacon, subject to the privileges of the class of operator license held.

(b) A beacon must not concurrently transmit on more than 1 channel in the same amateur service frequency band, from the same station location.

(c) The transmitter power of a beacon must not exceed 100 W.

(d) A beacon may be automatically controlled while it is transmitting on the 28.20-28.30 MHz, 50.06-50.08 MHz, 144.275-144.300 MHz, 222.05-222.06 MHz, or 432.300-432.400 MHz segments, or on the 33 cm and shorter wavelength bands.

(e) Before establishing an automatically controlled beacon in the National Radio Quiet Zone or before changing the transmitting frequency, transmitter power, antenna height or directivity, the station licensee must give written notification thereof to the Interference Office, National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944.

(2) If an objection to the proposed operation is received by the FCC from the National Radio Astronomy Observatory at Green Bank, Pocahontas County, WV, for itself or on behalf of the Naval Research Laboratory at Sugar Grove, Pendleton County, WV, within 20 days from the date of notification, the FCC will consider all aspects of the problem and take whatever action is deemed appropriate.

(f)A beacon must cease transmissions upon notification by a District Director that the station is operating improperly or causing undue interference to other operations. The beacon may not resume transmitting without prior approval of the District Director.

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